Solved

Debugging PHP Code

Posted on 2011-02-18
7
831 Views
Last Modified: 2012-08-13
Please provide some pointers on debugging PHP code. Having syntax errors in code, displays a completely blank screen and we have no idea where / what the problem is.

Examples:
1. Having <? php instead of <?php   at the top of the file

2. Having
    $categories[] = array('id' => $row['id'], 'name' => $row['name']); 'selected' => FALSE);
    instead of
    $categories[] = array('id' => $row['id'], 'name' => $row['name'], 'selected' => FALSE);

Thanks
0
Comment
Question by:caliea
7 Comments
 
LVL 38

Expert Comment

by:Aaron Tomosky
ID: 34928198
You can stick a die('made it to here');
In you code to check. Put it halfway, see if it makes it. Then keep splitting by Half till you find the problem.
0
 
LVL 8

Accepted Solution

by:
PranjalShah earned 250 total points
ID: 34928309
You can add this two lines at top of your code..

ini_set('error_reporting',E_ALL);
ini_set('display_errors',1);
0
 
LVL 38

Expert Comment

by:Aaron Tomosky
ID: 34928455
You can also use eclipse and have real debugging. But that's a whole other topic.
0
Backup Your Microsoft Windows Server®

Backup all your Microsoft Windows Server – on-premises, in remote locations, in private and hybrid clouds. Your entire Windows Server will be backed up in one easy step with patented, block-level disk imaging. We achieve RTOs (recovery time objectives) as low as 15 seconds.

 
LVL 2

Assisted Solution

by:TimBare
TimBare earned 250 total points
ID: 34928468
the error reporting is the easiest way to see what line it's dying on, but as far as pointers go, make sure you have the correct number of ()'s around lines, make sure you have your ; at the end of each line, stringing multiple variables together are separated w/ a .
ex:
$var1 = "abc";
$var2 = "def";
echo $var1.$var2;

Open in new window

would return "abcdef";

if you're using a for loop, make sure your counter is increasing ($i++;) otherwise it won't ever exit...

0
 
LVL 8

Expert Comment

by:ropenner
ID: 34928946
look in your web server's log file for the errors, once you've enabled error reporting.

eg. /var/log/apache2/error.log for Ubuntu Linux
      c:\wamp\logs\apache_error.log  windows WAMP install
0
 
LVL 5

Expert Comment

by:onemadeye
ID: 34929929
Placed this at the top of the PHP file to display errors
<?php
error_reporting(-1); // Put 0 to remove all errors

Open in new window

0
 
LVL 109

Expert Comment

by:Ray Paseur
ID: 34930278
Once you get the errors to show up, you will probably be able to find what is wrong rather quickly.  The comment at ID:34928309 is correct.

If you still have trouble debugging after that point, please post the code and the error message.

FWIW, parse errors only show up one-at-a-time.  The parser stops at the first error.  So if you have written a lot of code with a lot of parse errors in it, you may find that you need many iterations to get all the errors out!
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Developers of all skill levels should learn to use current best practices when developing websites. However many developers, new and old, fall into the trap of using deprecated features because this is what so many tutorials and books tell them to u…
Since pre-biblical times, humans have sought ways to keep secrets, and share the secrets selectively.  This article explores the ways PHP can be used to hide and encrypt information.
Learn how to match and substitute tagged data using PHP regular expressions. Demonstrated on Windows 7, but also applies to other operating systems. Demonstrated technique applies to PHP (all versions) and Firefox, but very similar techniques will w…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question